AB0475 TRANSCRANIAL DIRECT CURRENT STIMULATION DECREASES CHRONIC PAIN IN PATIENTS WITH RHEUMATOID ARTHRITIS: A RANDOMIZED, CONTROLLED, DOUBLE-BLIND CLINICAL TRIAL
Authors: S. Pilotti, R. Cavalheiro Do Espírito Santo, B. França, L. Santos, M. L. Gasparini Vieira, T. J. Santos de Souza, B. Ermel, A. L. Mallmann, D. Pereira, W. Caumo, R. Xavier
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Rheumatoid Arthritis (RA) patients often present chronic pain that may persist beyond therapeutic control of objective signs of inflammation [1] and may cause significant physical and psychological impairments. Complex mechanisms encompassing peripheral and central sensitization seem to be involved [2]. In fibromyalgia patients, Transcranial Direct Current Stimulation (tDCS) appears to be effective for decreasing chronic pain symptoms [3]. <h3>Objectives</h3> To verify the effect of active tDCS on pain and clinical symptoms in RA patients. <h3>Methods</h3> This double-blind randomized pilot clinical trial recruited women aged between 18 and 70 years diagnosed with RA and stable (3 months) low inflammatory status (CRP &lt; 10 mg/L, ESR &lt; 20 mm/h, swollen joint count ≤ 1) and persistent pain (VAS-pain &gt; 4cm), from the Rheumatology ambulatory clinic of Hospital de Clínicas de Porto Alegre/Brazil. The patients were randomized into two different groups: active tDCS (A-tDCS) and Sham (S-tDCS). The 20 sessions of tDCS (2mA) were applied at home daily, for 20 min, 5 days/week. Main outcome was pain by visual analogue scale (VAS cm) after 4 weeks. Additional evaluations: pressure pain threshold (PPT,Kg), disease activity (DAS28-CRP), physical function (HAQ-DI), fatigue (FACIT-F), central sensitisation (Central Sensitization Inventory - CSI), and safety. The Paired-sample t test, the Wilcoxon test, the T-tests for independent samples, the Mann-Whitney test and the Generalized estimating equations (GEE) were performed using a gamma model were performed (accepted at p ≤0.05). <h3>Results</h3> Twelve patients have completed this pilot study (A-tDCS, n=6 and S-tDCS, n=6). At baseline, there are no differences in clinical features between groups (Table 1). After the 4-week intervention, the time of intervention was associated with changes on VAS-pain (p=0.004). There was between groups a trend towards a statistically significant difference for the A-tDCS group (p=0.063). Both groups had improvements on HAQ-DI, FACIT-F and CSI. On the other hand, the CRP, DAS28-CRP and PPT did not change (p&gt;0.05) in both groups (Table 1). All patients reported low intensity of itch as an adverse effect during the session of tDCS. <h3>Conclusion</h3> These preliminary findings revealed that daily treatment with tDCS compared to sham stimulation over 4 weeks may improve the chronic pain in RA patients, despite the placebo effect observed for physical function, fatigue, PPT and central sensitization. The intervention was well tolerated. Thus, tDCS appears to be a promising auxiliary tool in the treatment of patients with low-inflammation RA who have chronic pain, but larger and longer studies are needed to confirm this observation and optimize it. <h3>Reference</h3> [1] Mathias K et al. Curr Pain Headache Rep. 2021; 2. Cao Y et al. Mediat Inflamm. 2020;3. Caumo W et al. J Pain. 2022. <h3>Acknowledgements</h3> Sociedade Brasileira de Reumatologia (SBR). <h3>Disclosure of Interests</h3> None Declared.